There are many different textile production techniques currently available. These different techniques vary depending upon various factors including the nature of the color and application method. The dye class may be selected subject to the nature of the fiber, customer's demand, color brilliance and depth. Other factors impacting the choice of textile production techniques may include the percentage coverage of pattern and hand feel requirements.
There is a significant demand in the textile industry for brightly-colored textiles woven with a soft handle or touch. However, present methods for manufacturing such soft, brightly-colored textiles produce excess waste in the form of costs for using excess resources, time, and actual waste product produced.
For 100% cotton textiles, for example, the currently accepted technology utilizes the class of dyestuffs known as reactive dyes. Reactive dyes are a class of dyestuffs consisting of a chromophore (colored molecule) with a reactive linkage that fixes the chromophore to the hydroxyl site on a cellulose molecule. In order to achieve this fixation, however, there are several disadvantages. Although reactive printing accommodates soft hand and color brilliance, a number of processing steps are required. Commercial processing typically requires multiple steps. However, these steps lead to heavy additional costs added to the overall process due to the requirement of multiple rinsing and/or drying steps required between the respective stages. The additional rinse and/or drying steps add enormous additional costs and waste materials to the treatment process. Due to its lengthy processing route, which includes desizing, scouring, bleaching, mercerizing, printing, steaming, washing, drying, and finishing, where multiple washes occur in between several of the steps, the cost for using substantial amounts of energy, water, and chemicals is also high.
The desizing step may occur separately or in combination with other stages of the process used to pre-treat the yarn to weave fabrics prior to subsequent processing. Desizing typically comprises the use of enzymatic agents or oxidants. A chemical system is employed to depolymerize the polymer used during the sizing step. The depolymerization reduces the viscosity of the polymeric material used in the sizing step and improves the removal potential; however, this is only achieved by using large amounts of washing water. Washing steps are necessary prior to and/or after the chemical treatment. One of the disadvantages of this method is the production of a high volume of effluent stream containing a low concentration of the soils removed from the textile, which, when treated for final disposal, have a chemical oxygen demand. The effluent stream is normally mixed with the other waste or effluent streams produced from the textile processing. The nature and total volume of the effluent results in long and complex treatment processes before final disposal is undertaken. Therefore, in addition to time and expenses related to resources and waste removal, the amount of time for a textile to proceed through the reactive printing process is lengthy, which decreases the number of batches of textile manufactured for eventual sale.
Alternatively, organic pigments are used in about 45 to 60% of total textile printing. Organic pigment particles are essentially glued to the fabric with the help of a binder, such as an acrylic polymer emulsion, in the presence of a synthetic thickener, which provides printable viscosity to the pigment and binder. This mixture is also known as print paste. Although shorter processes, which provide economic advantages exist, there are disadvantages to these short cuts. Typically the resulting textile has a stiff hand feel, poor crock and abrasion fastness. Thickeners are used in an amount of 2 to 3.5% by weight of print paste. However, all of the non-volatile materials in the thickener become part of a dried film of the textile, which has an adverse effect on hand feel. Moreover, during consumer or home laundering, these thickeners used in print paste lead to poor crock fastness and abrasion marks on the printed fabric.
Synthetic thickeners are also known to react with electrolytes resulting in decreased viscosity of the print paste. A viscosity of 20000 to 25000 cPs is typically required to achieve printing fine outlines on cotton substrates. Thus, a synthetic thickener-based printing system has to be absolutely free from electrolytes in order to print fine outlines on cotton substrate. In order to prevent decreased viscosity, the use of a thickener with the highest possible yield, i.e., larger molecular size thickener, is possible but only if electrolytes are avoided. In fact, the most important factor affecting printability of pigment is the presence of electrolytes on poorly prepared substrates. Electrolytes on substrates cause flushing, which can be substantially avoided by increasing the concentration of the thickener. But by increasing the concentration of the thickener the resulting print fabric is harsher. Binders have a greater film hardness also contributing to a hard hand feel. Moreover, since the thickeners are also incorporated into the film structure and are high polymers with numerous polar groups, they necessarily form a harder film.
Therefore, there is a need for an improved method of manufacturing a soft, brightly-colored textile. This method of textile printing would cost the manufacturer less by being a shorter process, use fewer resources such as water, energy, chemicals, and the like, produce less waste product for disposing, and increase the amount of resulting soft, brightly-colored textiles produced.